Structural Deformations in Graphene under Laser Ablation

Graphene, with its extraordinary properties, is an excellent compound for a wide range of applications. Moreover, the ability of designing, controlling, and fabricating 3D structures based on graphene would be a breakthrough for manufacturing the new advanced nano-structures. Laser ablation is currently the only technique that allows patterning of free-standing substrates. In this study, we investigate the ablation of a single layer graphene under high energy pulses by using first-principles density functional theory and reactive molecular dynamics (RMD) simulations. To mimic the laser pulse irradiation, we locally heat the selected area of the graphene layer using a Nosé-Hoover thermostat and considered a range of thermally-heated areas with a radius from 2 to 100 Å, and temperature from 1000 to 10000 K. RMD studies indicate that the shape of the ablated area is not only a function of the pulse energy, but also the radius of the pulse beam. When the radius of pulse beam is smaller than 10 Å, no deformation in graphene is observed for pulses with temperature lower than 8000 Å. Additionally, our predicted trends in the size and shape of the ablated areas coincide well with the experimental results carried out using femtosecond laser beams on a micrometer scale.